Interposer and packaging substrate having the interposer

ABSTRACT

An interposer is provided, including a composite body and a plurality of conductive through vias penetrating the composite body. The composite body includes at least a main layer and at least a combining layer stacked on one another. The combining layer prevents the main layer from being cracked. The combining layer is more flexible than the main layer. The combining layer prevents the main layer from being cracked. Therefore, the main layer can be thinned on demands, and the interposer can be thinned accordingly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to semiconductor technologies, and, moreparticularly, to an interposer and a packaging substrate including theinterposer.

2. Description of Related Art

With the rapid development of electronic industry, electronic productsare designed to be low-profiled and compact-sized and have a variety offunctionality, and can operate at a high speed. To meet therequirements, an electronic product is provided with more and moreelectronic elements, and a conventional 2D planar integration technique(e.g., side-by-side) evolves into a 3D IC technique. The 3D IC techniqueintegrates a plurality of chips in a 3D space vertically, to achieve theobjective of miniaturization. The 3D IC technique differs from the 2D ICtechnique in that the 3D IC technique employs conductive structures thatconduct upper side and lower side of a chip and thus shortens the lengthof traces provided on the chip.

Since the 3D IC technique is not mature yet, a 2.5D IC technique acts asa transitional technology. The 2.5D IC technique solves the problem ofthe prior art that the reliability is reduced due to the mismatchbetween coefficients of thermal expansion (CTE) of the chip and apackaging substrate by providing an interposer between the chip and thepackaging substrate. Since the interposer and the chip are made ofsimilar materials, and have approximately the same CTEs, the mismatchproblem can thus be solved.

FIGS. 1A-1C illustrate a method of fabricating an interposer accordingto the prior art.

As shown in FIG. 1A, a plurality of through vias 100 are formed on acomplete sheet of a glass body 10.

As shown in FIG. 1B, a metal material is formed in the through vias 100to form conductive through vias 11.

As shown in FIG. 1C, a redistribution layer (RDL) 12 is formed on anupper side of the glass body 10, a lower side of the glass body 10 ispolished to expose the conductive through vias 11, and anotherredistribution layer 12′ is formed on the lower side of the glass body10 and exposed surfaces of the conductive through vias 11, such that theinterposer 1 is fabricated. The redistribution layers 12 and 12′ areelectrically connected to the conductive through vias 11. A plurality ofconductive pads 120 are disposed on the upper-side redistribution layer12. A plurality of conductive pads 120′ are disposed on the lower-sideredistribution layer 12′.

In a subsequent flip-chip process, as shown in FIG. 1D, a singulationprocess is performed on the interposer 1 along a cut route L shown inFIG. 1C, and the singulated interposer 1 is disposed between thepackaging substrate 8 and a semiconductor chip 9. Bottom ends of theconductive through vias 11 are electrically connected to the packagingsubstrate 8 via the conductive pads 120′. The conductive pads 120disposed on the upper-side redistribution layer 12 are electricallyconnected to the semiconductor chip 9.

In the prior art, the interposer 1 is made of a single material (i.e.,the glass body 10). As a thin interposer 1 is popular in the market, theglass body 10 has to have a thickness reduced accordinly. However, toothin the glass body 10 is likely to be cracked, and has a yield rateless than 50% . In the prior art, the thickness of the glass body 10 ofthe interposer 1 has to be more than 100 μm. Therefore, the interposer 1cannot be thinned any further.

Therefore, how to solve the problem of the prior art is becoming anurgent issue in the art.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems of the prior art, the presentinvention provides an interposer, including a composite body having atleast a main layer and at least a combining layer stacked on oneanother. The combining layer prevents the main layer from being cracked.The combining layer is more flexible than the main layer. The interposerfurther comprises a plurality of conductive through vias penetrating thecomposite body.

The present invention further provides a packaging substrate, comprisinga carrying structure and an interposer embedded in the carryingstructure. The interposer comprises a composite body and a plurality ofconductive through vias penetrating the composite body. The compositebody has at least a main layer and at least a combining layer stacked onone another. The combining layer prevents the main layer from beingcracked. The combining layer is more flexible than the main layer.

In an embodiment, the carrying structure includes a core layer, and theinterposer is embedded in the core layer; a built-up structure isdisposed on the core layer and electrically connected to the conductivethrough vias of the interposer; the core layer has an opening, and theinterposer is received in the opening.

In an embodiment, the main layer is made of glass, silicon or ceramics.

In an embodiment, the composite body has a plurality of the main layers,and the main layers are made of the same or different materials.

In an embodiment, the combining layer is made of an adhesive material ora dielectric material.

In an embodiment, the combining layer is disposed between any two of themain layers.

In an embodiment, the composite body has an outermost layer that is thecombining layer.

In an embodiment, a redistribution layer is disposed on the compositebody and electrically connected to the conductive through vias, and theredistribution layer has a plurality of conductive pads.

Through the use of the composite body, which comprises the main layerand the combining layer that is more flexible than the main layer andcan prevent the main layer from being cracked, the interposer and thepackaging substrate according to the present invention can be madethinner, as compared with a silicon interposer of the prior art thatcomprises a single material. For example, the main layer can be formedas thin as 25 μm. Therefore, the interposer can be thinned on demands.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the followingdetailed description of the preferred embodiments, with reference madeto the accompanying drawings, wherein:

FIGS. 1A-1C are cross-sectional diagrams illustrating a method offabricating an interposer according to the prior art;

FIG. 1D is a cross-sectional diagram of the interposer shown in FIGS.1A-1C during a subsequent process;

FIGS. 2A-2D are cross-sectional diagrams illustrating a method offabricating an interposer according to the present invention;

FIG. 2D′ is another embodiment of FIG. 2D;

FIG. 2E is a cross-sectional diagram illustrating a method offabricating a packaging substrate according to the present invention;

FIG. 2E′ is another embodiment of FIG. 2E;

FIGS. 2F and 2F′ are cross-sectional diagrams of subsequent processes ofFIGS. 2E and 2D′, respectively;

FIGS. 3-6 are cross-sectional diagrams of a composite body of aninterposer of another embodiment according to the present invention; and

FIG. 4′ is another embodiment of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

The following illustrative embodiments are provided to illustrate thedisclosure of the present invention, these and other advantages andeffects can be apparently understood by those in the art after readingthe disclosure of this specification. The present invention can also beperformed or applied by other different embodiments. The details of thespecification may be on the basis of different points and applications,and numerous modifications and variations can be devised withoutdeparting from the spirit of the present invention.

FIGS. 2A-2E are cross-sectional diagrams illustrating a method offabricating interposers 2 a, 2 a′ and 2 a″ and packaging substrates 2and 2′ according to the present invention.

As shown in FIG. 2A, a composite body 20 is provided. The composite body20 comprises a plurality of main layers 20 a and a plurality ofcombining layers 20 b stacked on one another. The main layers 20 a andthe combining layers 20 b and 20 b′ are made of different materials. Thecombining layers 20 b and 20 b′ are more flexible than the main layers20 a. Therefore, the combining layers 20 b and 20 b′ are less likely tobe cracked than the main layers 20 a when an external force is appliedthereto.

In an embodiment, the flexibility of the combining layers 20 b and 20 b′and the main layers 20 a is determined by Young's modules, which is areference for selecting a material.

The main layers 20 a are made of glass, silicon, or ceramics, such asAl₂O₃ and AIN (aluminum nitride). The combining layers 20 b and 20 b′are made of an adhesive material such as a resin or a dielectricmaterial, such as polyimide (PI) and benzocyclobutene (BCB). The mainlayers 20 a are made of the same or different materials.

The combining layer 20 b that is made of an adhesive material isdisposed between two main layers 20 a. The composite body 20 has anoutermost layer that is the combining layer 20 b′ that is made of adielectric material.

The thickness t of the main layers 20 a is less than 50 μm, e.g., 25 μm,or less. The combining layer 20 b that is made of an adhesive materialis very thin, and the thickness of the combining layer 20 b isneglected. The thickness a of the combining layer 20 b′ that is made ofa dielectric material is less than 10 μm, e.g., 5 μm, or less.

As shown in FIG. 2B, the composite body 20 is penetrated by laser toform a plurality of through vias 200.

As shown in FIG. 2C, a metal layer is formed in the through vias 200 toform conductive through vias 21 and fabricate an interposer 2 a. If themain layer 20 a is made of silicon, an insulation material has to beformed on walls of the through vias 200 first, and the metal material isformed on the insulation material thereafter.

As shown in FIG. 2D, a redistribution layer (RDL) 22 is formed on oneside (e.g., an upper side) of the composite body 20. The redistributionlayer 22 has an innermost circuit 22 b electrically connected to theconductive through vias 21 and an outermost circuit 22 a having aplurality of conductive pads 220, for fabricating another interposer 2a′.

In another embodiment, as shown in FIG. 2D′, redistribution layers 22and 22′ are formed on two opposite sides (i.e., the upper and lowersides) of the composite body 20, respectively, and electricallyconnected to the conductive through vias 21, to fabricate anotherinterposer 2 a″.

As shown in FIG. 2E, a singulation process is performed on theinterposer 2 a′ shown in FIG. 2D, and the singulated interposer 2 a′ isembedded in a carrying structure 23, to fabricate a packaging substrate2.

In an embodiment, the carrying structure 23 comprises a core layer 230such as packaging resin, and a built-up structure 231. The interposer 2a′ is embedded in the core layer 230 and exposed from the core layer230, and the built-up structure 231 is disposed on a lower side of thecore layer 230 and electrically connected to the conductive through vias21 of the interposer 2 a′.

In another embodiment, as shown in FIG. 2E′, the carrying structure 23′comprises a core layer 230′ such as resin, and two covering layers 231′formed on the core layer 230 a′. The core layer 230′ has an opening 232,and the interposer 2 a shown in FIG. 2C is received in the opening 232.A filling material 233 is filled in the opening 232 to fix theinterposer 2 a. The two covering layers 231′ cover the interposer 2 a. Acircuit structure (not shown) is then formed on the covering layers 231′and electrically connected to the conductive through vias 21 of theinterposer 2 a, to fabricate another packaging substrate 2′. In anotherembodiment, the two covering layers 231′ are formed by flowing glue intothe opening 232 to fix the interposer 2 a. The filling material 233 andthe two covering layers 231′ are made of the same material.

Take the structure shown in FIG. 2E as an example. In subsequentprocesses, as shown in FIG. 2F, at least one semiconductor chip 9 isdisposed in a flip-chip manner on the packaging substrate 2, and solderballs 24 are formed on the built-up structure 231. In an embodiment, thesemiconductor chip 9 is coupled to the interposer 2 a′ via a pluralityof conductive bumps 90 (including copper posts 90 a and a tin soldermaterial 90 b) and electrically connected to the redistribution layer 22and the conductive through vias 21.

As shown in FIG. 2F′, the semiconductor chip 9 can also be disposed in aflip-chip manner on the interposer 2 a″ shown in FIG. 2D (or theinterposers 2 a and 2 a′ having other configurations). In an embodiment,the semiconductor chip 9 is coupled via a plurality of conductive bumps90 to the interposer 2 a″ and electrically connected to theredistribution layers 22 and 22′ and the conductive through vias 21.

The interposer 2 a, 2 a′, 2 a″ according to the present invention hasthe composite body 20, which is designed to have the combining layer 20b′ 20 b′ more flexible than the main layer 20 a. By contrast, aninterposer of the prior art is made of a single material such as a glassbody. Therefore, the main layer 20 a (such as glass), even if being madeto be very thin, will not be cracked because the combining layer 20 b,20 b′ is flexible enough to prevent the main layer 20 a from beingcracked. The thickness t of the main layer 20 a can be reduced ondemands, such as 25 μm or even 5 μm, and the interposer 2 a, 2 a′, 2 a″can thus be thinned accordingly.

Since the combining layer 20 b, 20 b′ can prevent the main layer 20 afrom being cracked, the yield rate of the composite body 20 isincreased. For example, the thinned composite body 20 has a yield rategreater than 50%.

The packaging substrate 2, 2′, since being fabricated by embedding theinterposer 2 a, 2 a′, 2 a″ into the carrying structure 23, is farthinner than a stack structure of a packaging substrate and a siliconinterposer of the prior art.

FIGS. 3-5 show other embodiments of composite bodies 30, 40, 40′, 50 and60 of an interposer according to the present invention.

As shown in FIG. 3A, the composite body 30 comprises two main layers 20a and a combining layer 20 b′ made of a dielectric material that issandwiched between the two main layers 20 a.

In an embodiment, the main layers 20 a are made of the same material. Inanother embodiment, the main layers 20 a are made of differentmaterials.

As shown in FIG. 4, the composite body 40 comprises three main layers 20a and two combining layers 20 b made of an adhesive material that aredisposed among the main layers 20 a.

In an embodiment, the main layers 20 a are made of the same material. Ina composite body 40′ of another embodiment, as shown in FIG. 4′, themiddle one of the three main layers 20 a is made of ceramics, and thetwo outer ones are made of glass.

As shown in FIG. 5, the composite body 50 comprise two combining layers20 b′ made of a dielectric material, three main layers 20 a, and twocombining layer' 20 b made of an adhesive material stacked on oneanother, and the three main layers 20 a and the two combining layers 20b are sandwiched between the two combining layers 20 b′.

In an embodiment, the main layers 20 a are made of the same material. Inanother embodiment, the main layers 20 a are made of differentmaterials.

As shown in FIG. 6, the composite body 60 comprises a combining layer 20b′ made of a dielectric material and a main layer 20 a.

Therefore, the interposer 2 a, 2 a′, 2 a″ according to the presentinvention comprises a composite body 20, 30, 40, 40′, 50, 60 and aplurality of conductive through vias 21 penetrating the composite body20, 30, 40, 40′, 50, 60.

The composite body 20, 30, 40, 40′, 50, 60 comprises at least a mainlayer 20 a and at least a combining layer 20 b, 20 b′ stacked on oneanother. The main layer 20 a, 20 a′ is made of glass, silicon, orceramics. The combining layer 20 b, 20 b′ is more flexible than the mainlayer 20 a, 20 a′.

In an embodiment, the composite body 20, 30, 40, 40′, 50 has a pluralityof the main layers 20 a and 20 a′, and the main layers 20 a and 20 a′have the same or different materials.

In an embodiment, the combining layer 20 b, 20 b′ of the composite body20, 30, 40, 40′, 50 is disposed between any two main layer 20 a and 20a′.

In an embodiment, the composite body 20, 50, 60 has an outermost layerthat is the combining layer 20 b.

In an embodiment, the combining layer 20 b, 20 b′ is made of an adhesivematerial or a dielectric material.

The interposer 2 a′, 2 a″ further comprises a redistribution layer 22,22′ disposed on the composite body 20 and electrically connected to theconductive through vias 21, and the redistribution layer 22, 22′ has aplurality of conductive pads 220.

In a packaging substrate 2, 2′ according to the present invention, theinterposer 2 a, 2 a′, 2 a″ is embedded into a carrying structure 23, 23′

Through the use of the composite body, which comprises the main layerand the combining layer that is more flexible than the main layer andcan prevent the main layer from being cracked, the interposer and thepackaging substrate according to the present invention can be madethinner, as compared with a silicon interposer of the prior art thatcomprises a single material. Therefore, the interposer can be thinned ondemands and the yield rate is increased.

The foregoing descriptions of the detailed embodiments are onlyillustrated to disclose the features and functions of the presentinvention and not restrictive of the scope of the present invention. Itshould be understood to those in the art that all modifications andvariations according to the spirit and principle in the disclosure ofthe present invention should fall within the scope of the appendedclaims.

What is claimed is:
 1. An interposer, comprising: a composite bodycomprising: a first main layer of a material selected from the groupconsisting of glass, silicon and ceramic, a second main layer of amaterial selected from the group consisting of glass, silicon andceramic, and an adhesive layer disposed between the first main layer andthe second main layer, wherein the adhesive layer is in direct surfacecontact with the first and second main layers and combines the firstmain layer to the second main layer; and a plurality of conductivethrough vias passing through the composite body, wherein a thickness ofthe adhesive layer is smaller than a thickness of each of the first andsecond main layers: the composite body has a first outermost layer thatis a first dielectric layer, the first dielectric layer is disposed onthe first main layer, and each of the conductive through vias has astraight sidewall that extends continuously, without interruption,through the first dielectric layer, the first main layer, the adhesivelayer, and the second main layer; wherein a conductive material of eachof the conductive through vias extends continuously, withoutinterruption, through the first dielectric layer, the first main layer,the adhesive layer, and the second main layer; and wherein the firstdielectric layer is in direct surface contact with the first main layer,is more flexible than the first and second main layers, and has athickness greater than the thickness of the adhesive layer.
 2. Theinterposer of claim 1, wherein the adhesive layer comprises polyimide(PI) or benzocyclobutene (BCB).
 3. The interposer of claim 1, whereinthe composite body has a second outermost layer that is a seconddielectric layer, the second dielectric layer is disposed on the secondmain layer, and the conductive material and the sidewall of each of theconductive through vias extend continuously, without interruption,through the first dielectric layer, the first main layer, the adhesivelayer, the second main layer, and the second dielectric layer.
 4. Theinterposer of claim 1, further comprising: a redistribution layerdisposed on the first dielectric layer and electrically connected to theconductive through vias, wherein the redistribution layer has aplurality of conductive pads.
 5. The interposer of claim 1, wherein theadhesive layer is more flexible than the first and second main layers.6. The interposer of claim 3, wherein the second dielectric layer is indirect surface contact with the second main layer, is more flexible thanthe first and second main layers, and has a thickness greater than thethickness of the adhesive layer.
 7. The interposer of claim 3, furthercomprising: a first redistribution layer disposed on top of the firstdielectric layer and electrically connected to the conductive throughvias; and a second redistribution layer disposed on bottom of the seconddielectric layer and electrically connected to the conductive throughvias, wherein a number of conductive layers in the second redistributionlayer is greater than a number of conductive layers in the firstredistribution layer.
 8. The interposer of claim 6, wherein thethickness of each of the first and second dielectric layers is less than10 μm.
 9. The interposer of claim 7, further comprising: a chip on topof and electrically coupled to the first redistribution layer.
 10. Theinterposer of claim 7, further comprising: a packaging material wrappingfour sides of both the composite body and the first redistributionlayer, wherein the second redistribution layer extends over and covers abottom of the packaging material.
 11. A packaging substrate, comprising:a carrying structure; and an interposer embedded in the carryingstructure and comprising: a composite body comprising: a first mainlayer of a material selected from the group consisting of glass, siliconand ceramic, a second main layer of a material selected from the groupconsisting of glass, silicon and ceramic, a third main layer of amaterial selected from the group consisting of glass, silicon andceramic, a first adhesive layer disposed between the first main layerand the second main layer, wherein the first adhesive layer is in directsurface contact with the first and second main layers and combines thefirst main layer to the second main layer, a second adhesive layerdisposed between the second main layer and the third main layer, whereinthe second adhesive layer is in direct surface contact with the secondand third main layers and combines the second main layer to the thirdmain layer, a first outermost layer that is a first dielectric layer,the first dielectric layer disposed on the first main layer, a secondoutermost layer that is a second dielectric layer, the second dielectriclayer disposed on the third main layer; a plurality of conductivethrough vias passing through the composite body; a first redistributionlayer disposed on top of the first dielectric layer and electricallyconnected to the conductive through vias; and a second redistributionlayer disposed on bottom of the second dielectric layer and electricallyconnected to the conductive through vias, wherein a number of conductivelayers in the second redistribution layer is greater than a number ofconductive layers in the first redistribution layer.
 12. The packagingsubstrate of claim 11, wherein the carrying structure comprises a corelayer, and the interposer is embedded in the core layer.
 13. Thepackaging substrate of claim 11, wherein a thickness of the secondredistribution layer is greater than a thickness of the firstredistribution layer.
 14. The packaging substrate of claim 11, whereineach of the first and second adhesive layers comprises polyimide (PI) orbenzocyclobutene (BCB).
 15. The packaging substrate of claim 11, whereinthe first and third main layers are made of the same material, and thesecond main layer is made of a material different from the material ofthe first and third main layers.
 16. The packaging substrate of claim11, wherein a thickness of each of the first and second adhesive layersis smaller than a thickness of each of the first, second and third mainlayers.
 17. The packaging substrate of claim 12, wherein the core layerhas an opening, the interposer is received in the opening, and thecarrying structure further comprises: a filling material filled in theopening to fix the interposer, wherein the filling material inside theopening covers upper, lower and side surfaces of the interposer, and anupper covering layer covering an upper surface of the core layer and anupper surface of the filling material in the opening, and a lowercovering layer covering a lower surface of the core layer and a lowersurface of the filling material in the opening.
 18. The packagingsubstrate of claim 16, wherein the first dielectric layer is in directsurface contact with the first main layer, is more flexible than thefirst, second and third main layers, and has a thickness greater thanthe thickness of each of the first and second adhesive layers, and aconductive material and a sidewall of each of the conductive throughvias extend continuously, without interruption, through the firstdielectric layer, the first main layer, the first adhesive layer, thesecond main layer, the second adhesive layer, and the third main layer.19. The packaging substrate of claim 18, wherein the second dielectriclayer is in direct surface contact with the third main layer, is moreflexible than the first, second and third main layers, and has athickness greater than the thickness of each of the first and secondadhesive layers, and the conductive material and the sidewall of each ofthe conductive through vias extend continuously, without interruption,through the first dielectric layer, the first main layer, the firstadhesive layer, the second main layer, the second adhesive layer, thethird main layer and the second dielectric layer.
 20. A packagingsubstrate, comprising: a carrying structure; and an interposer embeddedin the carrying structure and comprising: a composite body comprising: afirst main layer of a material selected from the group consisting ofglass, silicon and ceramic, a second main layer of a material selectedfrom the group consisting of glass, silicon and ceramic, a third mainlayer of a material selected from the group consisting of glass, siliconand ceramic, a first adhesive layer disposed between the first mainlayer and the second main layer, wherein the first adhesive layer is indirect surface contact with the first and second main layers andcombines the first main layer to the second main layer, and a secondadhesive layer disposed between the second main layer and the third mainlayer, wherein the second adhesive layer is in direct surface contactwith the second and third main layers and combines the second main layerto the third main layer; and a plurality of conductive through viaspassing through the composite body, wherein a thickness of each of thefirst and second adhesive layers is smaller than a thickness of each ofthe first, second and third main layers, the composite body has a firstoutermost layer that is a first dielectric layer, the first dielectriclayer is in direct surface contact with the first main layer, is moreflexible than the first, second and third main layers, and has athickness greater than the thickness of each of the first and secondadhesive layers, a conductive material of each of the conductive throughvias extends continuously, without interruption, through the firstdielectric layer, the first main layer, the first adhesive layer, thesecond main layer, the second adhesive layer, and the third main layer,the composite body has a second outermost layer that is a seconddielectric layer, the second dielectric layer is in direct surfacecontact with the third main layer, is more flexible than the first,second and third main layers, and has a thickness greater than thethickness of each of the first and second adhesive layers, theconductive material of each of the conductive through vias extendscontinuously, without interruption, through the first dielectric layer,the first main layer, the first adhesive layer, the second main layer,the second adhesive layer, the third main layer and the seconddielectric layer, and the thickness of each of the first and seconddielectric layers is less than 10 μm.